1.6.0 (2026-04-25)

Note: OpenMetrics 2.0 support is still in progress and not ready for general use yet.

As part of the OM2 work, metric-name suffix handling moved from metric creation time to scrape
time. A positive side effect is that metric names are now more flexible across the board, for
example names ending in suffixes like _total are accepted where they were previously rejected.
To keep the Prometheus and OM1 output unambiguous, the registry tracks claimed exposition names
and still rejects registrations that would collide at scrape time.

Example	Before 1.6.0	Since 1.6.0	Reason
Gauge("foo_total")	Rejected	Allowed	Not breaking because this previously failed at registration, so no working setup changes behavior, and safe because _total suffix expansion applies to counters, not gauges.
Counter("events_total")	Rejected	Allowed	Not breaking because the OM1 output is still events_total; only the builder now accepts the name.
Gauge("foo_total") + Histogram("foo")	Rejected	Allowed	Not breaking because this combination used to be blocked even though the exposed names do not overlap.
Gauge("events_total") + Counter("events")	Rejected	Rejected	Not breaking because the ambiguous OM1 output would still expose two events_total series.
Gauge("foo_count") + Histogram("foo")	Allowed	Rejected	Intentionally breaking because the old behavior could expose a conflicting foo_count name at scrape time.

Features

• Relax metric name validation in Dropwizard5 (#1985) (deb782f)

Bug Fixes

• deps: update dependency com.google.guava:guava to v33.6.0-jre (#2021) (1382693)
• deps: update dependency commons-io:commons-io to v2.22.0 (#2044) (9e05c1d)
• deps: update dependency io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha to v2.27.0-alpha (#2022) (30ac534)
• deps: update dependency io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha to v2.27.0-alpha (#2023) (2d51a32)
• deps: update dependency io.prometheus:prometheus-metrics-bom to v1.5.1 (#2004) (650ce4b)
• deps: update dependency org.apache.tomcat.embed:tomcat-embed-core to v11.0.21 (#2005) (7a36df7)
• deps: update dependency org.springframework.boot:spring-boot-starter-parent to v4.0.5 (#2006) (0106c18)
• deps: update dependency org.springframework.boot:spring-boot-starter-parent to v4.0.6 (#2046) (40a9db8)
• deps: update jetty monorepo to v12.1.8 (#2007) (acab5b2)
• deps: update protobuf (#2024) (8e2214e)
• pass release tag as input to deploy workflow (#1982) (165c921)
• pin grafana/otel-lgtm to 0.7.2 in OATs acceptance test (#1992) (f17ad9a)
• stabilize flaky timer and thread count tests (#1973) (ce5867b)
• trigger Maven deploy from release-please via workflow_dispatch (#1981) (698f956)